In particular, closing elements of this type are used as so-called expanders in holes with different diameters and internal pressures. Different embodiments are produced depending on the size of the hole and the strength of the effective internal pressure. A closing element of the type specified at the start is disclosed in WO 2009/000317 A1. The closure described here is characterised by simple production and equally simple operation, but at the same time has the disadvantage that it can only be used with small to moderate internal pressures. With higher internal pressures the secure anchoring of the closure to the wall of the hole to be closed is not always guaranteed.